Grid-controlled microwave thermionic device

ABSTRACT

A grid-controlled VHF thermionic device which can be used as an amplifier or a generator of VHF electromagnetic oscillations and which has two grid-leads forming, together with a cathode lead, two lines for feeding in the energy of a VHF electromagnetic field, the two lines being connected in parallel for the currents and voltages of said electromagnetic field.

United States Patent [191 Leliovsky et al. [451 Apr. 3, 1973 [54] GRID-CONTROLLED MICROWAVE [56] References Cited THERMIONIC DEVICE UNITED STATES PATENTS [76] Inventors: Anton Felixovich Leliovsky,

prospekt smimova 24 korpus 2 2,951,172 s/196o Grifmhse: al 313/341 x 3,305,748 2/1967 Pene et al 313/348 lll'abigngll f 'lfrl'lfa lgxalcfmfglf 3,164,740 1/1965 Moscony et a1. 313/348 9 a 9 1 Karl Romanovich Tern Grazhdan- 2,002,207 5/ 1935 MacLaren ..313/304 X sky prospekt, 27, kv. 152; Kira prima ry Examiner- David Schonber Boleslavovna Yankevlch insa s h' Assistant Examiner-PaulA. Sacherg komaya l5 kv' 26 au of Lenin Attorney-Holman, Glascock, Downing and Seebold grad, U.S.S.R. [22] Filed: June 22, 1970 [57] ABSTRACT [21] App1 N0 48,305 A grid-controlled VHF thermionic device which can be used as an amplifier or a generator of VHF electromagnetic oscillations and which has two grid-leads [52] U.S. Cl. ..313/302, 313/306, 313/307, forming together with a Cathode lead, two lines for 313/341. 313/348 3.15/39 feeding in the energy of a VHF electromagnetic field, [5l] l'ft' Cl "H011 U46 H011 21,10 Holl U15 the two lines being connected in parallel for the cur- [58] Fleld of Search ..313/302, 304, 305-307,

rents and voltages of said electromagnetic field.

2 Claims, 8 Drawing Figures PATENTEDAPN ISYS 4 3725,71?

SHEET l UF 3 GRID-CONTROLLED MICROWAVE TIIERMIONIC DEVICE The present invention relates to the microwave technology, and more particularly to grid-controlled microwave thermionic devices for generation and amplification of microwave oscillations. y

There exist grid-controlled microwave thermionic devices, comprising a common anode, an array of a plurality of spaced cathode elements; an array of a plurality of elements of at least one control grid disposed between said cathode elements and said anode wherein one grid lead and a cathode lead disposed con-centri cally form an input supply system or line (these terms are utilized as equivalents herein) for microwave ener- EY- A disadvantage of' the existing microwave devices is their low natural resonance frequency at the input thereof, which markedly lowers their bandwidth coefficient (the product of the gain by the passband) at frequencies exceeding their natural resonance frequency. v

An object of the present invention is to obviate this disadvantage.

A specific object of the present invention is to provide a grid-controlled microwave thermionicdevice with a high natural resonance frequency at the input thereof, lying within the working frequency range of the device.

This object is attained in a grid-controlled microwave thermionic device comprising a common anode and an array of a plurality of spaced cathode elements; an array of a plurality of elements of at least one control grid disposed between said cathode elements and said anode wherein the concentrically disposed cathode and grid leads form an input line through `which the energy of a microwave electromagnetic field is applied, in which device there is provided, according to the invention, an additional grid lead arranged concentrically with respect to said leads and forming with one of said leads a second input line that is connected in parallel to said input line for the currents and voltages of the VHF electromagnetic field.

In grid-controlled microwave thermionic devices comprising a control grid and a screen grid it is preferable to dispose the additional grid lead concentrically inside the control grid lead, and to connect it to the screen grid.

In grid-controlled microwave thermionic device comprising one control grid, the additional grid lead can be disposed inside the cathode lead.

In such devices the input resistance of the gridcathode gap provides load for two lines which are electrically connected in parallel for the currents and volt ages of the VHF electromagnetic field and whose resistance must be of inductive character with respect to the resonance frequency. A parallel connection of two inductances leads to a reduction in the equivalent total inductance. Thus, by reducing the input impedance of one of the input lines, for instance, by short-circuiting the currents and voltages of the VHF electromagnetic field inside the vacuum shell of the device it is possible to raise practically to unlimited values the natural input resonance frequency of the device, enabling it to operate on the main wavelength of oscillations of the electromagnetic field propagating in the coaxial line.

Compared with the known devices operating on higher harmonics, this reduces at least by per cent the reserves of reactive energy in the input oscillatory system, i.e., raises the bandwidth efficiency of the device.

The use of the herein disclosed microwave device for amplification of microwave oscillations in broad-band operation raises its power gain by approximately four times. This makes it possible to place less stringent requirements on the preamplifier, e.g. to reduce the number of its stages, to improve the 'reliability and other performance characteristics of the amplifier as a whole.

The invention will be best understood from the following description of its specific embodiment when read in connection with the accompanying drawings, in which:

FIG. 1 is a simplified longitudinal sectional view of a VHF tetrode, according to the invention;

FIG. 2 is a simplified longitudinal sectional view of a VHF triode, according to the invention.

FIG. 3 shows a cross section of the tetrode along III-III of FIG. 1.

FIG. 4 shows a perspective view showing the interior of the tetrode of FIG. l.

FIG. 5 is a top view of the tetrode of FIG. l.

FIGS. 7, 8 and 6 are corresponding views of the triode of FIG. z.

The grid-controlled VHF thermionic device (FIGS. 1-4) is a tetrode comprising an anode l, an array of cathode elements 2, each of which is placed inside a respective element of the control grid 3. The elements of the control grid 3 are disposed inside the respective elements of a screen grid 4 which are fixed on a cathode flange 5. A cathode lead 6 and a control grid lead 7 form a single coaxial input line, while the control grid lead 7 and an additional lead 8 of the screen grid form a second coaxial input line which is electrically connected in parallel with the rst line for the currents and voltages of the VHF electromagnetic field.

Screen grid 4 is electrically connected to the system of elements of the cathode 2 for the currents and voltages of the VHF electromagnetic field. These input lines are used to feed the energy of the microwave eletromagnetic field from an external source when the device operates as an amplifier, or from the anode circuit (not shown) of the device, when the latter operates as an oscillator. Ceramic rings 9, 10 and 11 are parts of the shell, through which the energy of the H.F. elec trom'agnetic field is fed in and out. Besides, these rings isolate the electrodes of the device for D.C. voltage.

The microwave tetrode operates as follows.

The energy of the microwave electromagnetic field is fed to the space between the cathode 2 and the control grid 3 through coaxial inputs formed by the leads 6-7 and 7-8.

Acted upon by the H.F. field and the screen grid voltage the stream of electrons passes through the control and screen grids to the anode 1 to excite a microwave field in the space between the anode and the screen grid, the energy of the microwave field being fed out through the ceramic ring 1l.

The grid-controlled VHF thermionic device (FIGS. 6-8) is a triode comprising an anode 12, an array of cathode elements 13, each of which is' placed inside a respective element of a control grid 14 which are fixed on a grid flange l5. The cathode lead 16 and the control grid lead 17 form a single input coaxial line, while an additional lead 18 of the control grid and the cathode lead 16 form a second coaxial input line which is connected in parallel to the first line for the currents and voltages of the VHF electromagnetic field.

These input lines are used to feed microwave energy from an external source when the device operates as an amplifier or from the anode circuit (not shown) of the device, when the latter operates as an oscillator. Ceramic rings 19, 20, 21 are parts of the shell, through which the energy of the microwave electromagnetic tield is fed in and out. Besides, these rings isolate the electrodes of the device for D.C. voltage.

The microwave triode operates as follows.

The energy of the microwave electromagnetic field is fed to the space between the cathode 13 and the control grid 14 through the coaxial inputs formed by the leads 16-17 and 16-18. Acted upon by the H.F.field and the D.C.field of the anode the stream of electrons passes through the control grid to the anode 12. to excite a microwave field in the space between the anode and the control grid, the energy of this field being fed out through the ceramic ring 21.

What is claimed is:

1. An electronic microwave thermionic device comprising, in combination, an anode comprising a body of revolution, a system of a plurality of `cathode elements; said cathode elements arranged along a circle; a first input radio-frequency lead comprising a body of revolution electrically connected to said system of a plurality of cathode elements; a system of a plurality of elements of a control grid; said elements of the control grid being arranged along a circle between said anode and said cathode elements; a second input radiofrequency lead comprising a body of revolution electrically connected to said system of a plurality of elements of the control grid; a third input radio-frequency lead comprising a body of revolution electrically connected to said system of a plurality of elements of the control grid; said anode, said system of a plurality of cathode elements, and said system of a plurality of elements of the control grid together with all said input radiofrequency leads being disposed concentrically with respect to one another; a first input coaxial system means for producing a microwave input defined by said first input radio-frequency lead electrically connected to said system of a plurality of cathode elements and said second input radio-frequency lead electrically connected to said system of a plurality of elements of the control grids; a second input coaxial system means for providing a microwave input formed by said first input radio-frequency lead electrically connected to said system of a plurality of cathode elements and said third radio-frequency lead electrically connected to said system of a plurality of elements of the control grid; both said first and second input coaxial systems being electrically connected parallel to each other.

2. An electronic microwave thermionic device comprising, in combination: an anode comprising a body of revolution; a system of a plurality of cathode elements; said cathode elements lead electrically connected to said system of a plurality of elements of the screen grid; both said first and second input coaxial systems being electrically connected ig palkralll t?l each other. 

1. An electronic microwave thermionic device comprising, in combination, an anode comprising a body of revolution, a system of a plurality of cathode elements; said cathode elements arranged along a circle; a first input radio-frequency lead comprising a body of revolution electrically connected to said system of a plurality of cathode elements; a system of a plurality of elements of a control grid; said elements of the control grid being arranged along a circle between said anode and said cathode elements; a second input radio-frequency lead comprising a body of revolution electrically connected to said system of a plurality of elements of the control grid; a third input radio-frequency lead comprising a body of revolution electrically connected to said system of a plurality of elements of the control grid; said anode, said system of a plurality of cathode elements, and said system of a plurality of elements of the control grid together with all said input radio-frequency leads being disposed concentrically with respect to one another; a first input coaxial system means for producing a microwave input defined by said first input radio-frequency lead electrically connected to said system of a plurality of cathode elements and said second input radio-frequency lead electrically connected to said system of a plurality of elements of the control grids; a second input coaxial system means for providing a microwave input formed by said first input radio-frequency lead electrically connected to said system of a plurality of cathode elements and said third radio-frequency lead electrically connected to said system of a plurality of elements of the control grid; both said first and second input coaxial systems being electrically connected parallel to each other.
 2. An electronic microwave thermionic device comprising, in combination: an anode comprising a body of revolution; a system of a plurality of cathode elements; said cathode elements lead electrically connected to said system of a plurality of elements of the screen grid; both said first and second input coaxial systems being electrically connected in parallel to each other. 